1. Field of the Invention
The present invention relates to a management apparatus, a management system, an operation status determination method, and an image forming apparatus.
2. Description of the Related Art
In electrophotographic image forming apparatuses, such as copiers, printers, facsimile apparatuses, or printing presses, an image is formed such that an electrostatic latent image of image data of an original is firstly formed on a photosensitive element that serves as a latent image carrier. The electrostatic latent image is then developed with toners supplied from a developing device. A developed image is lastly fixed on a recording medium such as a sheet. In such image forming apparatuses, various events may cause degradation of performance of the image forming apparatuses. For example, if an image forming apparatus includes an image carrier, such as a photosensitive element or an intermediate transfer belt, the image carrier is worn out because of friction by operation over time. Furthermore, abnormal situations occur in the image forming apparatus due to various reasons. For example, the dusts such as paper pieces from externals to an inside of the image forming apparatus may cause a failure. Toners are undesirably remained on the components because of increased toner adhesion due to excessive toner agitation caused by unexpected operation. Arrangements of components are disturbed due to unexpected operation. A cleaning unit is worn out and fails to remove toners. Performance of a charging unit is degraded due to dusts or an accidental event.
One outcome of such abnormal situations is degradation of image quality of an obtained image. For example, the obtained image contains a disturbing portion such as an unwanted line in a longitudinal direction or in a lateral direction, a faint portion, a stain, a pinhole, or a background fog. However, the image forming apparatus keeps performing operation even in the abnormal situation as long as mechanical components work. Therefore, only after the incomplete image is output, a user can recognize presence of an abnormality or occurrence of a failure in the image forming apparatus. At this state, the image forming apparatus needs to be recovered and the user needs to form the image again, so that a large amount of time and resources are consumed. The electrophotographic image forming apparatus generally has a complicated structure containing a large number of components. The components are subjected to various events that may cause a failure. Therefore, maintenance needs to be performed regularly to prevent occurrence of a failure.
Conventional technologies for predicting occurrence of a failure based on status data of an image forming apparatus so that effective service operation can be attained are disclosed in the following documents.
For example, Japanese Patent Application Laid-open No. 2003-215986 discloses a system that predicts a failure based on the number of occurrence of events indicative of a failure.
In the system, data to be collected is limited to the number of occurrence of events. Therefore, types of failures to be predicted are limited.
Furthermore, Japanese Patent Application Laid-open No. H5-164800 discloses a diagnosis method and a diagnosis apparatus. In this technology, data indicative of occurrence of a failure in a copier and status data of the copier are collected on a server, and a cause of a particular error is detected by statistical processing.
In this technology, data is transmitted from the copier to the server via a network, causing an increase of network loads. Furthermore, the server needs to integrally perform processing on a large amount of copiers, so that capacity of the server needs to be large enough to perform a large amount of calculations, increasing system configuration costs.
Moreover, Japanese Patent Application Laid-open No. 2001-175328 discloses a system and a method for detecting a cause of a failure in a single copier by integrally using data about sensors and counters in the copier. Specifically, a virtual sensor based on quantitative analysis using a hybrid diagnosis is arranged, data is formatted by an event generator, and the diagnosis system as a qualitative analysis device is used in a hybrid manner to diagnose a failure or predict a failure.
In this method, a maintenance sign determination is performed by a copier, so that loads on a management system is small. However, the maintenance sign determination is executed using a method that causes large calculation loads, such as a neutral network or a Bayesian inference. Therefore, loads on a processing device or a memory device in the copier increase, causing delay in operation of the copier, such as image processing or mechanical control, resulting in decrease of a processing speed.
Furthermore, Japanese Patent Application Laid-open No. 2005-17874 discloses a technology for predicting a failure. Specifically, a signal indicating a failure is detected first from among signals output from various sensors in an image forming apparatus (sign detection). Then, an index value is calculated based on various types of data, so that change of status of the image forming apparatus is determined based on data indicating how the index value changes over time.
In this technology, it is possible to determine whether a device is in a normal state, a failure state, or a maintenance sign detected state, using a statistical and mathematical method by digitizing a status signal obtained from a sensor or operation control data. In this state, a status index is generated based on a distance between status data using a method such as Fisher's linear discriminant or cluster analysis. In this method, status data is normalized for appropriately generating a homogeneous space to generate a status index based on a distance between status data in different units. However, the effective normalization methods are limited. Therefore, sufficient results cannot always be obtained. For example, in the MT method, data is normalized based on variation in a normal state using a Mahalanobis distance. However, this method is not always effective. Alternatively, it is possible to determine whether a maintenance sign is detected by qualitatively evaluating operation control data or a status signal obtained from a sensor. However, it is difficult to generate a method for appropriately evaluating a plurality of pieces of status data that largely change and in different units for an image forming apparatus having a complicated structure. Therefore, it takes a long time to perform maintenance sign determination, so that unnecessary operation may be performed during the long maintenance sign determination. Furthermore, outcome of the maintenance sign determination does not always match an actual operation status of a device. In this case, a diagnosis needs to be made through a trial and error process. Therefore, the diagnosis cannot be performed in a practical manner and even a diagnosis control device or the like needs to be provided. As a result, necessary costs increase.
Japanese Patent Application Laid-open No. H5-281809 discloses a method of detecting a failure on a particular unit or a component in an image forming apparatus.
Furthermore, Japanese Patent Application Laid-open No. H5-100517, Japanese Patent Application Laid-open No. H7-36323, Japanese Patent Application Laid-open No. H7-104616, Japanese Patent Application Laid-open No. 2001-356655, or Japanese Patent Application Laid-open No. 2000-270141 discloses a method for predicting a lifetime of a particular unit or a component in an image forming apparatus or a method for diagnosing occurrence of a failure based on the lifetime.
Moreover, Japanese Patent Application Laid-open No. H8-137344, or Japanese Patent Application Laid-open No. 2000-89623 discloses a method for detecting abnormality on a toner image caused by a failure in an image forming apparatus.
Furthermore, Japanese Patent Application Laid-open No. H5-323740, Japanese Patent Application Laid-open No. H7-104619, Japanese Patent Application Laid-open No. 2004-219617 discloses a method for optically detecting a state of the surface of a photosensitive element.
The image forming apparatuses are used in various locations such as offices or factories. Furthermore, environmental or mechanical conditions such as temperature, humidity, type of sheets, operation amount, or image patterns depend on locations or users of the image forming apparatuses. Because of variation in the conditions, statuses of the components or supplies (e.g., toners, developers, charging units, photosensitive elements, or cleaners) in the image forming apparatuses may be disturbed depending on time, places, or the like, so that prompt maintenance is necessary. However, with the conventional technologies, it is difficult to appropriately recognize a sign of a failure in consideration with various conditions. Therefore, it is difficult to promptly perform maintenance.